1. Field of the Invention
The invention relates to a safety device intended for a switching appliance formed by assembling together several removable modular elements.
2. Description of the Prior Art
It concerns more particularly, but not exclusively, a switching appliance of a type similar to that described in the U.S. Pat. No. 84 14826 filed in the name of the Applicant, which includes :
switching module comprising one or more switches each having at least one fixed contact element, at least one mobile contact element, mounted on a mobile assembly so as to be able to take up at least two positions, namely a first position in which the mobile contact element is applied against the fixed contact element (closed condition) and a second position in which the mobile contact element is moved away from the fixed contact element (open condition) and resilient means exerting on the mobile assembly a force tending to bring the mobile contact element back into the first position, PA1 a direct switching control module such, for example, as an electromagnet adapted to cause a change of condition of the switch by exerting on the mobile assembly an action antagonistic to that of the resilient means, PA1 an indirect switching control module having at least two stable conditions, namely a set condition and a tripped condition, as well as two transitory phases, namely a manual setting phase and a tripping phase, this module comprising means adapted for accumulating a given amount of potential energy during the setting phase and tripping means for applying this potential energy on a member actuating the mobile assembly of the switch during the tripping phase in response to a tripping order, and PA1 a protection module adapted to emit the tripping order, for example following an overload or a current surge. PA1 a "stop" position, and PA1 an "auto" position.
An important advantage of this type of appliance is that it is possible to remove or fit the control modules on the switching module without having to disconnect the circuit in which this latter is connected.
Now, for obvious safety reasons, these operations must necessarily take place without causing a change of condition of the switch and, preferably, in the open condition of the switch.
This means then that the direct switching module is in the de-energized condition and can then not exert a closure action of the mobile assembly of the switch and, moreover, the indirect switching module is in the set condition.